🔧 Transmission Fluid - Fluid Change

This procedure covers a standard drain-and-fill on the 6-speed automatic in your Sierra. The key is to use the correct fluid, refill through the fill port, and verify the level at the proper transmission temperature.

Difficulty Level: Intermediate | Estimated Time: 2-3 hours

---

⚠️ Safety & Precautions

• Work on a level surface and support the truck securely with jack stands before getting underneath.
• Transmission fluid can be hot. Let the truck cool before draining it.
• Keep dirt out of the transmission. Clean the area around the fill, drain, and level plugs before opening them.
• You must verify fluid level at the correct transmission temperature. A scan tool that reads transmission fluid temperature is required.
• No battery disconnect is required for this service.

---

🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands (rated for truck weight)
• Wheel chocks
• Drain pan
• 3/8-inch ratchet
• Torx T40 socket
• 15mm socket
• Torque wrench
• Fluid transfer pump (specialty)
• Scan tool with transmission fluid temperature live data
• Funnel
• Safety glasses
• Nitrile gloves
• Shop towels

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission fluid, Dexron VI - Qty: 1 case
• Transmission pan gasket - Qty: 1
• Transmission filter - Qty: 1
• Transmission pan bolts - Qty: 1 set
• Drain plug seal - Qty: 1

---

📋 Before You Begin

• Park on level ground and set the parking brake.
• Chock the rear wheels before lifting the truck.
• If your goal is a full service, plan to replace the filter and pan gasket while the pan is off.
• Have the scan tool ready before refilling. You need transmission temperature to finish the level check.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise and secure the truck

• Use the floor jack to lift the front of the truck, then support it with jack stands.
• Keep the truck level as much as possible so the fluid level check is accurate.

Step 2: Remove the skid shield if equipped

• Use the 15mm socket to remove the shield bolts.
• Set the shield aside and keep the hardware organized.

Step 3: Drain the transmission

• Position the drain pan under the transmission.
• Use the Torx T40 socket to remove the drain plug.
• Let the fluid drain fully.
• Install a new drain plug seal if equipped.
• Torque the drain plug to 25 Nm (18 ft-lbs).

Step 4: Remove the transmission pan

• Use the 3/8-inch ratchet and 15mm socket to loosen the pan bolts evenly.
• Leave a few bolts loosely threaded on one side while you lower the other side to control the fluid spill.
• Remove the pan and drain the remaining fluid.
• Tip: Keep the pan level while lowering it.

Step 5: Replace the filter and gasket

• Remove the old filter by hand or with a gentle pull.
• Install the new transmission filter fully into place.
• Clean the pan thoroughly with shop towels.
• Install the new transmission pan gasket on the pan.
• Reinstall the pan and start all bolts by hand.
• Torque the pan bolts to 8 Nm (71 in-lbs).

Step 6: Refill the transmission

• Use the fluid transfer pump to add Dexron VI automatic transmission fluid through the fill port.
• Fill until fluid begins to slightly dribble from the level/check port.
• Install the fill plug loosely for now.

Step 7: Warm the transmission and set the final level

• Start the engine and foot-brake the truck in Park.
• Use the scan tool to monitor transmission fluid temperature.
• Shift slowly through each gear, pausing 2-3 seconds in each position, then return to Park.
• When the transmission reaches the correct temperature range, remove the level/check plug.
• Add fluid with the fluid transfer pump until a thin stream drips from the level port.
• Torque the level/check plug to 25 Nm (18 ft-lbs).
• Torque the fill plug to 25 Nm (18 ft-lbs).

Step 8: Reinstall the shield and lower the truck

• Use the 15mm socket to reinstall the shield, if equipped.
• Lower the truck carefully with the floor jack.

---

✅ After Repair

• Start the truck and check underneath for leaks.
• Road test gently and make sure shifts feel normal.
• Recheck the fluid level if you see any leaks or abnormal shifting.
• If the fluid was badly worn or the transmission had issues, scan for transmission codes after the test drive.

---

💰 DIY vs Shop Cost

Shop Cost: $280-$500 (parts + labor)

DIY Cost: $90-$180 (parts only)

You Save: $190-$320 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-2.5 hours.

---

🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.